Adding add-on board

docs/source/understand.rst

@@ -6,6 +6,7 @@ This section is dedicated to explaining how the esieabot's basic components work
 .. toctree:: 
     :maxdepth: 2
 
+    understand/add-on-board/add-on-board
     understand/raspberrypi/raspberrypi
     understand/dcmotor/dcmotor
     understand/l293d/l293d

docs/source/understand/add-on-board/add-on-board.rst

+Add-on board
+============
+
+Since 2023, the esieabot has been equipped with a dedicated PCB to control its motors. It also adds new components such as an LED and an integrated button or an analog/digital converter.
+
+.. image:: add-on-board.png
+   :width: 300
+   :align: center
+
+Components
+----------
+
+The esieabot add-on board is equipped with a DRV8411 motor controller from Texas Instrument as well as a TLA2024 analog-to-digital converter. The ADC is connected to the :doc:`Raspberry Pi</understand/raspberrypi/raspberrypi>` I2C bus.
+
+
+Used pins
+---------
+
+The add-on board connects a few components directly to the Raspberry Pi GPIOs as follows:
+
+* Button on GPIO 6
+* LED on GPIO 26
+* Motor controls on GPIO 17, 22, 23 and 25
+* Servo motors on GPIO 18 and 13
+* Speed sensors on GPIO 4 and 16
\ No newline at end of file

docs/source/understand/l293d/l293d.rst

@@ -5,7 +5,7 @@ L293D H-Bridge
    :width: 300
    :align: center
 
-Your esieabot is equipped with an L293D H-bridge enabling it to control these 2 :doc:`dc motors</understand/dcmotor/dcmotor>` in all directions.
+Your esieabot (from 2020 to 2022) is equipped with an L293D H-bridge enabling it to control these 2 :doc:`dc motors</understand/dcmotor/dcmotor>` in all directions.
 
 Operation
 ---------